The major objective of this program of research is to understand both the moderating influences of skill acquisition (e.g., consistency, complexity, transfer) and which human abilities limit performance, specifically how the performance-abilities relationship changes as a function of adult age. These data, together with previous and normative data, will drive the development and refinement of a format model of the interactions of aging, automatic/controlled processing and skill acquisition. The proposed research will lead to progress in several aspects of an age-related understanding of attention, automatism, and skill acquisition. First, through the application of experimental techniques and new tasks an enhanced understanding will be gained about the similarities and differences among age groups both within and between phases of skill development. Second, the present IDs approach will allow specification of the underlying abilities associated with skill development for old and young adults. Normative research has shown that older individuals learning new skills generally do not reach pure automatic processing. However, the IDs approach will identify, regardless of age groups, those individuals that do develop automatic processing, identify what abilities are limiting their performance, and identify what abilities are limiting performance of those individuals that do not reach automatism. Hence, the proposed program of research will determine the basis causes and manifestations of IDs across phases of skill acquisition within and between age groups; thus a primary focus will be acquiring the basis descriptive data necessary for that task. In addition, a theoretical approach is extrapolated in an effort to understand, predict, and perhaps reduce IDs in learning. This theoretical perspective offers a distinct advantage over previous approaches to understanding, predicting and remediating IDs in learning in that the approach integrates cognitive/ information processing theories of skill acquisition with more traditional psychometric/differential theories of intellectual abilities. The second major thrust of the proposal is the development and refinement of a formal model. This modeling effort will allow consolidation of the many findings across a relatively wide range of tasks and facilitate the development of a "globally parsimonious" theory of aging and complex performance.